Download So what does genetics have to do with Evolution

Evolutionary Vocabulary
I.
Define the following terms IN YOUR OWN WORDS:
a. Mutation – change in the nucleotide base sequence of a gene or DNA molecule (202)
b. Trait – a variation of a characteristic. In genetics, traits are the phenotype of an allele.
c. Allele – synonymous with trait in genetics.It a variation of a gene.
d. Frequency – (refers to allele frequency) the proportion of gene copies in a population that are a specific
allele. Calculated by dividing the number of copies of an allele of the gene, but the total number of
genes (of all alleles). Frequencies are reported in decimal form. The frequencies of all possible alleles
should sum to 1.0
e. Drift (Genetic) – the random change in allele frequency in a population. This was demonstrated in the
Zoobia lab with the Tsunami
f. Population – a group of organisms of the same species that live in a specific geographic area and
interbreed. (362, 381). In genetics, population genetics are the study of the frequency and interaction of
alleles and genes within populations.
II.
Answer the following
1. In one sentence each describe how a mutation could be:
a. Bad: A mutation can be bad if it results in a lower survivability (of the species)
b. Neutral: A mutation is neutral if it neither increases nor decreases survivability (of the species)
c. Good: A good mutation is one that allows for viable offspring to be produced, generally at a
higher rate than before that mutation had occurred.
d. From the definitions above, put together a definition for “Allele frequency”.
the proportion of gene copies in a population that are a specific allele. Calculated by dividing the
number of copies of an allele of the gene, but the total number of genes (of all alleles). Frequencies are
reported in decimal form. The frequencies of all possible alleles should sum to 1.0
2. How might allele frequency explain why isolated populations (populations that don’t have emigration
or immigration) of people tend to have similar traits?
If an allele is abundant in a population it increases the likelihood of it being passed to the next
generation if there are no new alleles introduced or taken out of the population.
3. Picture your average Irish person and your average Japanese person. Name two genetic traits that you
think have extremely different allele frequencies in the Irish population as compared to the Japanese
population. EXPLAIN.
Skin pigment (Irish are often quite pale. The genes that relate to eye socket shape may also be quite
different, as well as hair texture.
4. How might a major natural disaster that dramatically reduces the population size, change the allele
frequencies and therefore the average traits of a population?
Since individuals are randomly killed, one would expect alleles having low frequency to either disappear,
or become a larger part of the population. This would either increase or decrease that frequency. As can be
seen in the Zoobia lab, we can also have little change in the percentage of some alleles
5.
Evolution is defined as a population changing over time. It does NOT necessarily mean they become a
whole new species. For example: Female giraffes prefer long necked males for mating to short necked
males. How might this preference cause a shift in the gene frequencies over time? How will the
population change?
Children would at least carry a long-necked gene. This would maintain this allele. The short-necked
genes would decrease, and over several generation may disappear (although in many populations, the
“less desired” phenotype is occasionally mated with (perhaps to maintain variation). We know it
happens, we are not sure how the females know to do this.